package com.issc.util;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.net.JarURLConnection;
import java.net.URL;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Set;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

/**
 * 类加载器
 */
public class ClassUtil {
    //日志
    private static final Logger LOGGER= LoggerFactory.getLogger(ClassUtil.class);
    //获取类加载器
    private static ClassLoader getClassLoader(){
        return Thread.currentThread().getContextClassLoader();
    }
    //加载类
    public static Class<?> loadClass(String className,boolean isInitialized){
        Class<?> clazz;
        try {
            clazz=Class.forName(className,isInitialized,getClassLoader());
        }catch (ClassNotFoundException e){
            LOGGER.error("load class failure",e);
            throw new RuntimeException(e);
        }
        return clazz;
    }
    /**
     * 获取指定包名下的所有类
     */
    public static Set<Class<?>> getClassSet(String packageName){
        Set<Class<?>> classSet=new HashSet<>();
        try {
            Enumeration<URL> urls=getClassLoader().getResources(packageName.replace(".","/"));
            while (urls.hasMoreElements()){
                URL url=urls.nextElement();
                if (url!=null){
                    String protocol=url.getProtocol();
                    if (protocol.equals("file")){
                        String packagePath=url.getPath().replaceAll("%20"," ");
                        addClass(classSet,packagePath,packageName);
                    }else if (protocol.equals("jar")){
                        JarURLConnection jarURLConnection= (JarURLConnection) url.openConnection();
                        if (jarURLConnection!=null){
                            JarFile jarFile=jarURLConnection.getJarFile();
                            if (jarFile!=null){
                                Enumeration<JarEntry> jarEntries=jarFile.entries();
                                while (jarEntries.hasMoreElements()){
                                    JarEntry jarEntry=jarEntries.nextElement();
                                    String jarEntryName=jarEntry.getName();
                                    if (jarEntryName.endsWith(".class")){
                                        String className=jarEntryName.substring(0,jarEntryName.lastIndexOf("."))
                                                .replaceAll("/",".");
                                        doAddClass(classSet,className);
                                    }
                                }
                            }
                        }
                    }
                }
            }
        } catch (IOException e) {
            LOGGER.error("get classSet failure",e);
            throw new RuntimeException(e);
        }
    return classSet;
    }

    private static void addClass(Set<Class<?>> classSet, String packagePath, String packageName) {
        File[] files=new File(packagePath).listFiles(file -> ((file.isFile())&&file.getName().endsWith(".class"))||file.isDirectory());
        if (files!=null) {
            for (File file:files){
                String fileName=file.getName();
                if (file.isFile()){
                    String className=fileName.substring(0,fileName.lastIndexOf("."));
                    if (StringUtils.isNotEmpty(packageName)){
                        className=packageName+"."+className;
                    }
                    doAddClass(classSet,className);
                }else {
                    String subPackagePath=fileName;
                    if (StringUtils.isNotEmpty(packagePath)){
                        subPackagePath=packagePath+"/"+subPackagePath;
                    }
                    String subPackageName=fileName;
                    if (StringUtils.isNotEmpty(packageName)){
                        subPackageName=packageName+"."+subPackageName;
                    }
                    addClass(classSet,subPackagePath,subPackageName);
                }
            }
        }
    }

    private static void doAddClass(Set<Class<?>> classSet, String className) {
        Class<?> cls=loadClass(className,false);
        classSet.add(cls);
    }
}
